The present invention relates to an intermediate rib for collapsible umbrella, and more particularly to an umbrella intermediate rib that is not easily subject to bending and deformation, so that the stretched umbrella has a graceful appearance and the collapsed umbrella has even reduced volume.
As shown in FIG. 1A, a common collapsible umbrella mainly includes a telescopic shaft 11 consisting of multiple segments, a hub 12 mounted to a top of the shaft 11, a runner 13 slidably put around the shaft 11 to move up, and down along the shaft 11, multiple sets of rib arrangements (A), and a cover 14 connected to and covering top of the rib arrangements (A).
Each set of the rib arrangement (A) includes an inner rib 2, an intermediate rib 3, an outer rib 4, a stretcher 5, an inner tie 6, and an intermediate tie 7 that are connected to one another in a predetermined manner. The inner rib 2 is pivotally connected at an inner end 2a to the hub 12 and at an outer end 2b to the intermediate rib 3 close to, an inner end 3a thereof, the stretcher 5 is pivotally connected at an inner end 5a to the runner 13 and at an outer end 5b to the inner rib 2 close to a middle 2c thereof, the inner tie 6 is pivotally connected at an inner end 6a to the stretcher 5 close to the outer end 5b thereof and at an outer end 6b to the inner end 3a of the intermediate rib 3, the intermediate rib 3 is pivotally connected at the inner end 3a to the outer end 6b of the inner tie 6 and at an outer end 3b to the outer rib 4 close to an inner end 4a thereof, and the intermediate tie 7 is pivotally connected at an inner end 7a to the inner rib 2 close to the outer end 2b the of and at an outer end 7b to the inner end 4a of the outer rib 4. As can be seen from FIGS. 1B and 1C, the intermediate rib 3 is an open-topped U-shaped member and is provided near a middle point of one side wall thereof with a lug 31 that is bent to flatly lie across the open top of the U-shaped rib 3, so that a passage 32 is provided between the bent lug 31 and the U-shaped rib 3. The intermediate tie 7 is adapted to extend through the passage 32 in order to slide in the U-shaped intermediate rib 3 below the bent lug 31 when the umbrella is stretched or collapsed.
In each set of the rib arrangement, the inner rib 2, the stretcher 5, and the intermediate rib 3 are mainly provided to serve as supports and therefore usually have an U-shaped cross section. The intermediate tie 7 and the outer rib 4 need to elastically bend when the umbrella is stretched or collapsed and when the umbrella is subject to a strong wind pressure and therefore usually have a round cross section and are flexible. As to the inner tie 6, it may be either an U-shaped or a round member.
In brief, the conventional intermediate rib 3 for collapsible umbrella is provided with an U-shaped cross section to achieve the projected supporting effect. Such U-shaped intermediate rib 3 has, however, the following disadvantages:
1. When a user stretches the umbrella while walks or while there is wind blowing against the stretched umbrella, the cover of the umbrella, particularly an outer periphery of the cover, is subject to a downward wind pressure (F). At this point, the flexible outer rib 4 having a round cross section would naturally elastically bend in a direction the same as that of the wind to avoid deformation or breaking thereof. The wind pressure (F) also applies on the outer end 3b of the intermediate rib 3. As mentioned before, the entire intermediate rib 3 has an U-shaped cross section and is therefore a rigid instead of a flexible member. When the cover 14 of the stretched umbrella is subject to a high wind pressure (F), the rigid intermediate rib 3 would fail to elastically bend in response to the wind pressure applied on it and tends to deform and become damaged near the inner end 3a thereof.
2. The conventional U-shaped rigid intermediate rib 3 is not adapted to naturally and elastically bend under the tension of the cover 14. And, since the outer end 3b of the intermediate rib 3 is pivotally connected to the outer rib 4 close to the inner end 4a thereof, there are clearances existing between the intermediate rib 3 and the cover 14. Areas of the cover 14 above such clearances tend to form undesirable depressions 15 when the umbrella is stretched.
3. The U-shaped intermediate rib 3 has two side-walls 33 that necessitate a large space W for the outer end 3b of the intermediate rib 3 to pivotally connect to the outer rib 4. The side walls 33 of the intermediate rib 3 also make the collapsed umbrella to occupy a large space.
Another problem with the conventional intermediate rib 3 is that the intermediate tie 7 extended through the passage 32 below the bent lug 31 of the intermediate rib 3 is slightly bent and deformed at a point below the lug 31. Therefore, the intermediate tie 7 undesirably frictionally contacts with two ends of the bent lug 31 when it moves relative to the intermediate rib 3 at the time the umbrella is stretched or collapsed, preventing the umbrella from stretching or collapsing smoothly.
It is therefore a primary object of the present invention to provide-an improved intermediate rib for collapsible umbrella, wherein the intermediate rib includes an U-shaped inner part that is adapted to support and pivotally connect to other appropriate ribs, and a round outer part that is sufficiently flexible to elastically bend in response to a wind pressure without becoming broken. The round outer part of the intermediate rib bends naturally under a tension of the cover of the umbrella when the latter is stretched, giving the stretched umbrella a smooth and graceful appearance. The round outer part of the intermediate rib, being without U-shaped walls, also enables the pivotal connection of the intermediate rib to the outer rib within a reduced space and to further reduce the collapsed volume of the umbrella.
Another object of the present invention is to provide an improved intermediate rib for collapsible umbrella, wherein the intermediate rib is associated with the intermediate tie with a collar. The intermediate tie has an U-shaped bend near a middle portion thereof with two sides of the U-shaped bend engaged into two axial guide slots provided at two ends of the collar, so that the intermediate tie is guided by the collar to slide along the intermediate rib without shifting sideward when the umbrella is stretched or collapsed.